This invention relates to vinyl terminated polyurethane compositions which may be copolymerized with ethylenically unsaturated monomers to produce thermoset polymers characterized by excellent corrosion resistance and high impact strength.
A variety of corrosion-resistant polymeric materials have been developed and used for the manufacture of chemical processing equipment such as ducts, pipe, hoods, stacks, processing tanks, storage tanks and the like for the handling of corrosive liquids and vapors. Although corrosion resistance is a major consideration in the selection of a polymer for such purposes, various other factors such as cost, ease of fabrication, mechanical strength, thermal stability, and impact resistance must also be considered. For example, the rate of failure of prior art corrosion resistant polymers through impact or vibration has been a major problem. Polyester resins such as those derived from bisphenol A and fumaric acid are noted for exceptional thermal and hydrolytic stability and have been used extensively in the manufacture of equipment which will withstand strong acids and bases, However, such polymers, even when reinforced with glass fiber and the like are brittle and tend to crack or fracture on impact or flexure. Cracks produced by impact or flexure often lead to chemical attack and deterioration, resulting in part from a wicking action at the damaged impact site. Various prior art attempts to produce polymeric materials having improved impact strength have generally resulted in a diminishing of corrosion resistance, thermal stability or other desirable property of the polymer.
It is known that the presence of urethane linkages may contribute to the corrosion resistance of a polymer. Thus, for example, it is known to prepare corrosion resistant polymers from monomers having urethane linkages and ethylenically unsaturated terminal groups. U.S. Pat. No. 3,297,745 discloses the preparation of such monomers by the reaction of one mole of a dihydric compound such as an alkylene, arylene or polyalkylene ether glycol, or a dihydric phenol such as a bisphenol, naphthalene diol, or the like with two moles of a diisocyanate to form a diisocyanate having two urethane linkages and subsequent reaction of the diurethane diisocyanate with two moles of an ethylenically unsaturated alcohol, such as an hydroxyalkyl acrylate. The resultant acrylate terminated tetraurethane monomer may polymerized or copolymerized with a vinyl monomer, such as styrene, to form corrosion-resistant polymers or copolymers.
A wide variety of other polyurethane compositions are known and used commercially in the preparation of molded articles, laminates, coatings, films, adhesives, rigid and flexible foams and the like. The wide variation of polyurethane compositions and properties thereof stems from the ability of isocyanates to react with a variety of organic compounds having active hydrogen-containing groups. Among the many such compositions known in the art are polyurethanes prepared from polyisocyanates and various polyols, including for example polyether polyols, polyester polyols, polydienediols, novolacs, oxyalkylated novolacs, and others.
In U.S. Pat. No. 3,278,293, for example, it is disclosed that improved physical properties and self-extinguishing characteristics may be obtained in polyurethane compositions derived from specific mixtures of polyether polyols, novolac resins and polyisocyanates.
U.S. Pat. No. 3,497,465 discloses the preparation of polyurethanes especially useful in low temperature applications from the reaction of an organic polyisocyanate with a composition comprising an oxyalkylated phenol-aldehyde resin, a polyol prepared by reacting a polyhydric alcohol and a mono epoxide, a dihydric alcohol, such as ethylene glycol, an alkanolamine, and a phosphorus compound.
U.S. Pat. No. 3,538,040 discloses the preparation of curing resins for foundry sands, by reacting an organic polyisocyanate with an oxyalkylated phenol-aldehyde or phenol-ketone condensate. U.S. Pat. No. 3,686,106 discloses curable foundry binders of an oil modified hydroxyalkylated novolac resin, an unsaturated petroleum polymer, a solvent and an organic polyisocyanate.
The foregoing prior art illustrates the wide variety of polyurethane compositions that may be prepared by reaction of a polyisocyanate and various polyols, including novolacs and oxyalkylated novolacs. It will be appreciated by those skilled in the art that despite the wide selection of known compositions and properties, a continuing need exists for new and better components and specific combinations of components for polyurethane compositions that will provide improved properties for various special applications, such as the manufacture of corrosion resistant articles and materials.
It is an object of this invention to provide novel polyurethane compositions which may be copolymerized with an ethylenically unsaturated monomer. It is a further object to provide novel thermoset polyurethane compositions well suited for use in the manufacture of corrosion-resistant articles of manufacture. It is a still further object to provide polymeric materials and articles of manufacture having superior corrosion resistant properties as well as high impact strength.